Murphy said that Tadesse used a buck knife--a type of hunting knife with an average blade length of six to eight inches--to stab her roommate and her roommate's friend.

The assistant district attorney also reported that the investigation into the case by the Harvard, Cambridge and state police is continuing.

The district attorney's office is focusing on the personal relationship between Tadesse and Ho.

The two were placed together in a double by chance at the beginning of sophomore year, after "floating" separately into Dunster House.

After rooming together for two years, their ties became strained, according to friends. Several weeks ago, Ho entered the Dunster housing lottery with Jennifer A. Tracy '97 and Malikah J. Sherman '96--and not Tadesse--several friends of Ho's said.

Statements from acquaintances of the two describe a relationship that had become increasingly fractured in recent months.

In contrast to some press reports, many Dunster residents said that the women never seemed especially close.

One friend who spoke frequently with both claimed not to have known they were roommates until the morning of the murder.

"I never heard about relations between them, whether they were good or not," said the friend.

"They weren't friends," said another sophomore in Dunster House who knew both women. "They didn't like each other."

After Ho decided not to room with Tadesse again next year, the soon-to-be killer is reported to have grown irrational.

Last month, Tadesse sent a one page letter to her roommate, Ho's sister Thao told The Boston Globe.

"I thought we were going to do stuff together, you'll always have a family to go to and I am going to have no one," Tadesse wrote, according to The Globe.

Tadesse is an Ethiopian citizen who attended the International Community School in the capital of Addis Ababa. Ho's immediate family lives in Medford, Mass.

But despite rooming problems between the two women, Murphy emphasized that authorities remain puzzled about Tadesse's motive in killing her roommate.

"I could still say we'd say this was an inexplicable event," Murphy said. "There'snever a really good reason for murder. But in thiscase, the nature of the crime, its suddenness,makes it different and less like many other crimesthat we investigate."

Murphy declined to comment on any specificpieces of evidence or theories for potentialmotives. Murphy did say that he had "no reason tobelieve" that there were any "romantic links"between the two, indicating that he was ruling outthe possibility of a jealously-tinged lovetriangle